Rubbers having a chemical crosslinking point by vulcanization cannot be recycled and have a high specific gravity. On the other hand, thermoplastic elastomers are composed of a phase separation structure containing a physical crosslinking point by crystallization or the like as a hard segment and an amorphous portion as a soft segment, so that the thermoplastic elastomers have such characteristic features that they are easily subjected to melt molding processing, are able to be recycled, and have a low specific gravity. Accordingly, the thermoplastic elastomers are watched in the fields of automobile parts, electric and electronic parts, sporting goods, and the like.
As the thermoplastic elastomers, there are developed a variety of thermoplastic elastomers such as polyolefin-based, polyurethane-based, polyester-based, polyamide-based, polystyrene-based, or polyvinyl chloride-based thermoplastic elastomers, etc. Of these, polyurethane-based, polyester-based, and polyamide-based thermoplastic elastomers are known as an elastomer having relatively excellent heat resistance.
Above all, polyamide elastomers are excellent in terms of flexibility, low specific gravity, friction resistance and abrasion resistance properties, elasticity, bending fatigue resistance, low-temperature properties, molding processability, and chemical resistance, so that they are widely used as materials of tubes, hoses, sporting goods, seal packings, and automobile or electric and electronic parts.
As the polyamide elastomers, there are known polyether polyamide elastomers containing a polyamide block as a hard segment and a polyether block as a soft segment, and the like. As examples thereof, Patent Documents 1 and 2 disclose polyether polyamide elastomers based on an aliphatic polyamide such as polyamide 12, etc.